1. Field
This disclosure relates generally to forming a semiconductor layer, and more specifically, to epitaxially growing a semiconductor layer that may be used, for example, in a photodetector.
2. Related Art
Some devices, such as photodetectors, are formed by epitaxially growing germanium over a silicon layer. It is important that the interface between the germanium and silicon is clean. If the interface is not clean then epitaxial growth is impeded and device performance is degraded. One approach to form a clean interface between the germanium and silicon involves thermally baking the substrate before forming the germanium at temperatures greater than approximately 800 degrees Celsius while flowing hydrogen gas. However, this temperature can damage the underlying silicon layer. In addition, if the photodetector is integrated with transistors on the substrate, the transistor, which are already formed, cannot withstand such a high temperature. Hence, a need exists for forming a clean interface between the germanium and silicon without the negative effects of the prior art method.